CN116184666A - Optical system comprising a light-guiding optical element with two-dimensional expansion - Google Patents

Abstract

The present disclosure relates to an optical system comprising a light guiding optical element with a two-dimensional extension. An optical system includes a light guiding optical element (LOE) having a first set of mutually parallel partially reflective surfaces and a second set of mutually parallel partially reflective surfaces oriented differently from the first set of mutually parallel partially reflective surfaces. Both sets of partially reflective surfaces are located between a set of mutually parallel major exterior surfaces. Image illumination introduced at the in-coupling location propagates along the LOE, redirected by the first set of partially reflective surfaces towards the second set of partially reflective surfaces where it is coupled out towards the user's eye. The first set of partially reflective surfaces is implemented as partial surfaces located at the locations required to fill the eye box with the desired image. Additionally or alternatively, the spacing of the first set of partially reflective surfaces varies across the first region of the LOE. Additional features relate to the relative orientation of the projector and the partially reflective surface to improve compactness and enable various adjustments.

Description

Optical system comprising a light-guiding optical element with two-dimensional extension

This application is a divisional application of an invention patent application with an application date of September 9, 2019, an application number of "201980057892.X", and an invention title of "Optical System Including a Light Guide Optical Element with Two-Dimensional Expansion".

technical field

The present invention relates to optical systems, and in particular it relates to optical systems comprising light guiding optical elements (LOEs) for achieving optical aperture expansion.

Background technique

Many near-eye display systems include a transparent light-guiding optical element (LOE) or "waveguide" placed in front of the user's eye, the LOE or waveguide transmits the image within the LOE by internal reflection, and is then coupled out towards the user's eye by a suitable output coupling mechanism. image. The outcoupling mechanism can be based on embedded partial reflectors or "facets", or it can employ diffractive modes. The following description will primarily relate to facet-based outcoupling devices, but it will be understood that the various features of the invention are also applicable to diffractive devices.

Contents of the invention

The present invention is an optical system.

In accordance with the teachings of embodiments of the present invention, there is provided an optical system for directing image illumination injected at an in-coupling region to an eye box for viewing by a user's eye, the optical system comprising a light guide optic formed of a transparent material An element (LOE), the LOE comprising: (a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation; (b) a second region comprising a second set of planar mutually parallel partially reflective surfaces in a second orientation; (c) a set of mutually parallel major outer surfaces extending across the first region and the second region such that the first set of partially reflective surfaces and A second set of partially reflective surfaces are located between the major outer surfaces, wherein the second set of partially reflective surfaces are at an oblique angle to the major outer surfaces such that internal reflections passing through the major outer surfaces propagate within the LOE from the first region to the second. A portion of the image illumination of the area is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that a portion of the image illumination from the in-coupling area propagates within the LOE through internal reflection at the main outer surface is deflected towards a second region, wherein each of the partially reflective surfaces of the first set of partially reflective surfaces comprises a partially reflective coating at an interface plane between two plates forming part of the LOE, and wherein the partially reflective coating A layer is located on a first portion of the interface plane, and at least one of the partially reflective surfaces has a second portion of the interface plane bonded to form an optical continuum between the two plates.

According to another feature of an embodiment of the present invention, propagating within the LOE from the in-coupling region, is deflected by one of the first set of partially reflective surfaces and along by one of the second set of partially reflective surfaces The envelope of the path of light rays outcoupled in the direction to the eye box defines an imaging area of one of the first set of partially reflective surfaces, and wherein the one of the first set of partially reflective surfaces located in the envelope The area outside the network defines a non-imaging area of one of the partially reflecting surfaces of the first set of partially reflecting surfaces, wherein a substantial portion of the non-imaging area is combined to form an optical continuum between the two plates.

According to another feature in an embodiment of the invention, the first set of partially reflective surfaces has a non-uniform spacing such that the spacing between adjacent partially reflective surfaces close to the in-coupling region is smaller than the spacing between adjacent partially reflective surfaces far from the in-coupling region. interval between.

According to another feature of an embodiment of the present invention, the optical system further includes an image projector for projecting a collimated image having an angular field of view around the optical axis, the image projector is optically coupled to the LOE to The collimated image is introduced into the LOE at the entry region as a propagated image propagating within the LOE by internal reflection at the main outer surface, the propagated image being partially reflected by the first set of partially reflective surfaces to generate the inner reflection at the main outer surface. reflecting a deflected propagating image propagating within the LOE, the deflected propagating image being partially reflected by a second set of partially reflective surfaces to generate an outcoupled image directed outward from one of the major exterior surfaces toward the eye box, the optical axis of the outcoupling image The tilt relative to the normal to the major outer surface has a non-zero tilt component along the in-plane extension of the second set of partially reflective surfaces.

According to another feature of an embodiment of the invention, it is configured to project an image to the eye box with a main axis including an X axis corresponding to a first horizontal or vertical axis of the projected image, and another axis corresponding to the projected image. axis corresponds to the Y-axis, and wherein the second set of partially reflective surfaces has a direction of extension parallel to the main outer surface, the direction of extension having an angular offset relative to the X-axis.

According to another feature of an embodiment of the invention, it is configured to project an image to the eye box with a main axis including an X axis corresponding to a first horizontal or vertical axis of the projected image, and another axis corresponding to the projected image. axis corresponding to the Y-axis, the optical system also includes an image projector for projecting a collimated image with an angular field of view around the optical axis, the image projector is optically coupled to the LOE to align the collimator at the in-coupling region A straight image is introduced into the LOE as a propagated image propagating within the LOE by internal reflection at the main outer surface, the in-plane component of the optical axis of the propagated image being inclined relative to the X-axis towards the boundary of the second region.

According to another feature of an embodiment of the invention, the in-plane component of one end of the field of view of the propagating image is substantially parallel to the X-axis.

According to another feature of an embodiment of the invention, it is configured to project an image to the eye box with a main axis including an X axis corresponding to a first horizontal or vertical axis of the projected image, and another axis corresponding to the projected image. axis corresponding to the Y-axis, the optical system also includes an image projector for projecting a collimated image with an angular field of view around the optical axis, the image projector is optically coupled to the LOE to align the collimator at the in-coupling region The straight image is introduced into the LOE as a propagated image propagating within the LOE by internal reflection at the main exterior surface, the propagating image being partially reflected by the first set of partially reflective surfaces to generate The deflected propagation image of , the in-plane component of the optical axis of the deflected propagation image is inclined with respect to the Y axis.

In accordance with the teachings of embodiments of the present invention there is also provided an optical system for projecting an image injected at an in-coupling region for viewing by a user's eye at an eye box, the image being viewed with a main axis comprising a An X-axis corresponding to the horizontal or vertical axis of the projected image, and a Y-axis corresponding to an axis perpendicular to the X-axis of the projected image, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOE comprising: (a) A first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation; (b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to the first orientation parallel partially reflective surfaces; (c) a set of mutually parallel major exterior surfaces extending across the first region and the second region such that the first set of partially reflective surfaces and the second set of partially reflective surfaces are located on the major exterior surface , wherein the second set of partially reflective surfaces is at an oblique angle to the main outer surface such that a portion of the image illumination propagating within the LOE from the first region to the second region by internal reflection at the main outer surface is directed from the LOE toward the eye outcoupling, and wherein the first set of partially reflective surfaces is oriented such that a portion of the image illumination propagating within the LOE from the incoupling region by internal reflection at the main outer surface is deflected toward the second region, and wherein the first set The two sets of partially reflective surfaces have directions of extension parallel to the main outer surface, directions of extension having an angular offset relative to the X-axis.

In accordance with the teachings of embodiments of the present invention there is also provided an optical system for projecting an image injected at an in-coupling region for viewing by a user's eye at an eye box, the image being viewed with a main axis comprising a An X-axis corresponding to the horizontal or vertical axis of the projected image, and a Y-axis corresponding to an axis perpendicular to the X-axis of the projected image, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOE comprising: (a) A first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation; (b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to the first orientation parallel partially reflective surfaces; (c) a set of mutually parallel major exterior surfaces extending across the first region and the second region such that the first set of partially reflective surfaces and the second set of partially reflective surfaces are located on the major exterior surface , wherein the second set of partially reflective surfaces is at an oblique angle to the main outer surface such that a portion of the image illumination propagating within the LOE from the first region to the second region by internal reflection at the main outer surface is directed from the LOE toward the eye outcoupling, and wherein the first set of partially reflective surfaces is oriented such that a portion of the image illumination propagating within the LOE from the incoupling region by internal reflection at the main outer surface is deflected toward the second region, the optical system further comprising An image projector for projecting a collimated image with an angular field of view around the optical axis, the image projector is optically coupled to the LOE to introduce the collimated image into the LOE at the in-coupling region as through the main outer surface Internal reflection at propagating image propagating within the LOE, the in-plane component of the optical axis of the propagating image is tilted with respect to the X-axis towards the boundary of the second region.

According to another feature of an embodiment of the invention, the in-plane component of one end of the field of view of the propagating image is substantially parallel to the X-axis.

In accordance with the teachings of embodiments of the present invention there is also provided an optical system for projecting an image injected at an in-coupling region for viewing by a user's eye at an eye box, the image being viewed with a main axis comprising a An X-axis corresponding to the horizontal or vertical axis of the projected image, and a Y-axis corresponding to an axis perpendicular to the X-axis of the projected image, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOE comprising: (a) A first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation; (b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to the first orientation parallel partially reflective surfaces; (c) a set of mutually parallel major exterior surfaces extending across the first region and the second region such that the first set of partially reflective surfaces and the second set of partially reflective surfaces are located on the major exterior surface , wherein the second set of partially reflective surfaces is at an oblique angle to the main outer surface such that a portion of the image illumination propagating within the LOE from the first region to the second region by internal reflection at the main outer surface is directed from the LOE toward the eye outcoupling, and wherein the first set of partially reflective surfaces is oriented such that a portion of the image illumination propagating within the LOE from the incoupling region by internal reflection at the main outer surface is deflected toward the second region, the optical system further comprising An image projector for projecting a collimated image with an angular field of view around the optical axis, the image projector is optically coupled to the LOE to introduce the collimated image into the LOE at the in-coupling region as through the main outer surface A propagating image propagating within the LOE by internal reflection at , the propagating image being partially reflected by the first set of partially reflective surfaces to generate a deflected propagating image propagating within the LOE by internal reflection at the main exterior surface, the deflected propagating image being The in-plane component of the optical axis is tilted with respect to the Y-axis.

According to another feature of embodiments of the invention, the eye box is delimited by at least one straight line parallel to the X-axis.

According to another feature of an embodiment of the invention, the projected image is a rectangular image with edges parallel to the X-axis and the Y-axis.

According to another feature of an embodiment of the present invention, there is also provided a support device configured to support the LOE relative to the user's head, wherein one of the main outer surfaces faces the user's eyes and along the The orientation of the eye such that the x-axis is oriented horizontally.

According to another feature of an embodiment of the invention, the first area and the second area are separated by a boundary extending parallel to the X-axis.

In accordance with the teachings of embodiments of the present invention, there is also provided an optical system for directing image illumination injected at an in-coupling region to an eye box for viewing by a user's eye, the optical system comprising a light guide formed of a transparent material An optical element (LOE), the LOE comprising: (a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation; (b) a second region comprising a second set of planar mutually parallel partially reflective surfaces in a parallel second orientation; (c) a set of mutually parallel major exterior surfaces extending across the first region and the second region such that the first set of partially reflective surfaces and a second set of partially reflective surfaces are located between the main outer surfaces, wherein the second set of partially reflective surfaces are at an oblique angle to the main outer surface such that internal reflections passing through the main outer surface propagate within the LOE from the first region to the second A portion of the image illumination of the second region is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that the portion of the image illumination propagating within the LOE from the in-coupling region by internal reflection at the main outer surface A portion is deflected toward the second region, and wherein the first set of partially reflective surfaces has a non-uniform spacing such that adjacent partially reflective surfaces near the incoupling region are less spaced apart than adjacent partially reflective surfaces farther from the incoupling region interval between.

In accordance with the teachings of embodiments of the present invention, there is also provided an optical system for directing image illumination injected at an in-coupling region to an eye box for viewing by a user's eye, the optical system comprising a light guide formed of a transparent material An optical element (LOE), the LOE comprising: (a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation; (b) a second region comprising a second set of planar mutually parallel partially reflective surfaces in a parallel second orientation; (c) a set of mutually parallel major exterior surfaces extending across the first region and the second region such that the first set of partially reflective surfaces and a second set of partially reflective surfaces are located between the main outer surfaces, wherein the second set of partially reflective surfaces are at an oblique angle to the main outer surface such that internal reflections passing through the main outer surface propagate within the LOE from the first region to the second A portion of the image illumination of the second region is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that the portion of the image illumination propagating within the LOE from the in-coupling region by internal reflection at the main outer surface A portion is deflected toward the second region, the optical system further includes an image projector for projecting a collimated image having an angular field of view around the optical axis, the image projector is optically coupled to the LOE for The collimated image is introduced into the LOE as a propagating image propagating within the LOE by internal reflection at the main exterior surface, the propagating image being partially reflected by the first set of partially reflective surfaces to generate a propagating image within the LOE by internal reflection at the primary exterior surface The propagated deflected propagating image is partially reflected by the second set of partially reflective surfaces to generate an out-coupling image directed outwardly from one of the main exterior surfaces to the eye box, the optical axis of the out-coupling image being relative to the main exterior The normal to the surface is tilted with a non-zero tilt component along the in-plane extension of the second set of partially reflective surfaces.

Description of drawings

The invention is herein described, by way of example only, with reference to the accompanying drawings, in which:

1A and 1B are schematic isometric views of optical systems implemented using light-guiding optical elements (LOEs) constructed and operative in accordance with the teachings of the present invention, showing top-down configurations and side-injection configurations, respectively;

Figures 2A and 2B are enlarged schematic isometric views of the LOE from Figure 1A or Figure 1B showing the ray paths of the two end fields of the image;

Figure 2C is a summary of the fields of Figures 1A and 1B combined with additional fields defining the overall envelope of partially reflective surfaces required to form a complete image at the eye box;

Figure 2D is an alternative implementation of Figure 2C in which partially reflective surfaces are selectively implemented;

Figure 2E is a view similar to Figure 2D showing variable spacing between partially reflective surfaces;

Figure 2F is a view similar to Figure 2E, showing the region that can be excised in the LOE;

3A and 3B are views similar to FIG. 2E showing potential ray paths that form ghosts with and without partially reflective surfaces outside the desired profile of the partially reflective surface;

FIG. 4A is an enlarged schematic isometric view of a first region of an LOE according to another implementation of the LOE of FIG. 1A or FIG. 1B , showing the ray paths of two end fields;

Figure 4B is a view similar to Figure 4A showing a partial representation of partially reflective surfaces with variable spacing between the partially reflective surfaces;

Figure 4C is a view similar to Figure 4B showing the portions of the partially reflective surface required for the end of field;

Figure 5A is an enlarged schematic isometric view of an LOE comprising a first region similar to that of Figure 4C implemented according to the principles shown above with respect to Figure 2E;

FIG. 5B is a view similar to FIG. 5A showing the resectable region of the LOE;

FIGS. 6A-6D are schematic isometric views similar to FIGS. 2A-2F showing the effect of various angular offset parameters; and

7 is a schematic top view of a near-eye display showing angular offsets required for facial curves and convergence correction in accordance with aspects of the present invention.

Detailed ways

Certain embodiments of the present invention provide an optical system comprising a Light Guide Optical Element (LOE) for optical aperture expansion for purposes of a heads-up display, and most preferably may be a virtual reality display or more preferably a Near-eye displays for augmented reality displays.

An exemplary implementation of a device in the form of a near-eye display (generally designated 10 ) employing an LOE 12 according to the teachings of embodiments of the present invention is shown schematically in FIGS. 1A and 1B . The near-eye display 10 employs a compact image projector (or "POD") 14 optically coupled to inject an image into an LOE (interchangeably referred to as a "waveguide," "substrate," or "panel") 12, in Image light in LOE 12 is captured in one dimension by internal reflection at a set of mutually parallel flat outer surfaces. The light is directed toward a set of partially reflective surfaces (interchangeably referred to as "facets") that are parallel to each other and obliquely inclined relative to the direction of propagation of the image light, where each successive facet deflects a portion of the image light into a deflection direction, which is also captured/guided within the substrate by reflection. This first set of facets is not shown separately in FIGS. 1A and 1B , but is located in the first region (designated 16 ) of the LOE. This partial reflection at successive facets enables optical aperture expansion in the first dimension.

In a first set of preferred but non-limiting examples of the invention, the aforementioned set of facets is normal to the main outer surface of the substrate. In this case both the injected image and its conjugate which undergoes internal reflection when propagating in the region 16 are deflected and become the conjugate image propagating in the direction of deflection. In an alternative preferred but non-limiting set of examples, the first set of partially reflective surfaces is at an oblique angle relative to the major outer surface of the LOE. In the latter case, the injected image or its conjugate forms the desired deflected image propagating within the LOE, while another reflection can be minimized, for example, by employing angle-selective coatings on the facets that make small The plane is relatively transparent to the range of angles of incidence presented by images that do not require its reflection.

The first set of partially reflective surfaces deflects image illumination from a first direction of propagation trapped within the substrate by total internal reflection (TIR) to a second direction of propagation also trapped within the substrate by TIR.

The deflected image is then irradiated into a second substrate region 18, which can be realized as an adjacent different substrate or as a continuation of a single substrate, in which outcoupling devices (further A set of partially reflective facets or diffractive optical elements) progressively couples a portion of the image illumination towards the eyes of the observer within the area defined as the eye movement box (EMB), thereby enabling optical aperture expansion in the second dimension. The unitary device can be implemented individually for each eye, and is preferably supported relative to the user's head, with each LOE 12 facing the corresponding eye of the user. In a particularly preferred option as shown here, the supporting device is realized as a spectacle frame with side parts 20 for supporting the device relative to the user's ear. Other forms of support devices may also be used, including but not limited to headbands, visors, or devices that hang from the helmet.

Reference is made herein to an X-axis and a Y-axis in the drawings and claims, wherein the X-axis extends horizontally (FIG. 1A) or vertically (FIG. 1B) along the general direction of extension of the first region of the LOE, and the Y-axis extends perpendicular to the X-axis. The axes extend, ie vertically in FIG. 1A and horizontally in FIG. 1B .

In very rough terms, the first LOE or first region 16 of LOE 12 may be considered to effect aperture expansion in the X direction, while the second LOE or second region 18 of LOE 12 effects aperture expansion in the Y direction. The details of the angular direction of the spread of the different parts of the field of view will be expressed more precisely below. It should be noted that the orientation shown in Figure 1A can be considered a "top-down" implementation in which image illumination entering the main (secondary region) of the LOE enters from the upper edge, whereas in Figure 1B The orientation shown may be considered a "side injection" implementation in which an axis referred to herein as the Y-axis is deployed horizontally. In the remaining figures, various features of certain embodiments of the invention will be shown in the context of a "top-down" orientation, similar to Figure 1A. However, it should be understood that all these features are equally applicable to side injection implementations which also fall within the scope of the present invention. Other intermediate orientations are also suitable in some cases and unless expressly excluded, other intermediate orientations are included within the scope of the invention.

The POD employed with the device of the present invention is preferably configured to generate a collimated image, ie in which the light of each image pixel is a parallel beam collimated to infinity, where the angular direction corresponds to the pixel position. Thus, the image illumination spans an angular range corresponding to the angular field of view in two dimensions.

Image projector 14 includes at least one light source typically deployed to illuminate a spatial light modulator, such as an LCOS chip. The spatial light modulator modulates the projected intensity of each pixel of the image to generate the image. Alternatively, the image projector may include a scanning device, typically implemented using a fast scanning mirror, that scans the illumination from the laser light source across the projector's image plane, while the intensity of the beam is varied synchronously with the pixel-by-pixel motion, thereby targeting Each pixel projects the desired intensity. In both cases, the collimating optics are set to generate an output projected image collimated to infinity. Some or all of the above components are typically arranged on the surface of one or more polarizing beam splitter (PBS) cubes or other prismatic devices known in the art.

The optical coupling of the image projector 14 to the LOE 12 can be achieved by any suitable optical coupling, for example, via a coupling prism with an input surface that is beveled, or via a reflective coupling device, via the side edges and/or the main outer surface of the LOE. one of the surfaces. The details of the coupling configuration are not critical to the invention and are shown schematically here as a non-limiting example of a wedge prism 15 applied to one of the main outer surfaces of the LOE.

It should be appreciated that near-eye display 10 includes various additional components, typically including controller 22 for actuating image projector 14, typically powered from a small on-board battery (not shown) or some other suitable power source. It should be appreciated that the controller 22 includes all necessary electronic components for driving the image projector, such as at least one processor or processing circuit, all of which are known in the art.

Turning now to FIGS. 2A-2F , the optical characteristics of an implementation of a near-eye display are shown in more detail. In particular, a more detailed view of a light guiding optical element (LOE) 12 formed of a transparent material is shown, the LOE 12 includes a first region 16 and a second region 18, the first region 16 containing a first set of flat surfaces having a first orientation. The second region 18 comprises a second set of planar mutually parallel partially reflective surfaces 19 having a second orientation non-parallel to the first orientation. A set of mutually parallel major outer surfaces 24 extends across the first region 16 and the second region 18 such that the first set of partially reflective surfaces 17 and the second set of partially reflective surfaces 19 are located between the major outer surfaces 24 . Most preferably, the set of major exterior surfaces 24 is a pair of surfaces each continuous across the entire first region 16 and second region 18, however the choice of increasing or decreasing thickness between regions 16 and 18 is also within the invention. range. Region 16 and region 18 may be immediately juxtaposed such that regions 16 and 18 meet at a boundary, which may be a straight boundary or some other form of boundary, or, depending on the particular application, there may be a One or more additional LOE regions in between to provide various additional optical or mechanical functions. Although the invention is not limited to any particular manufacturing technique, in some particularly preferred implementations the exceptionally high quality of the main exterior surface is achieved by employing continuous exterior panels sandwiching separately formed regions 16 and 18 to form a composite LOE structure.

The optical properties of the LOE can be understood by back-tracing the image illumination path. The second set of partially reflective surfaces 19 is at an oblique angle to the major outer surface 24 such that a portion of the image illumination propagating within the LOE 12 from the first region 16 to the second region 18 by internal reflection at the major outer surface travels from the LOE toward the eye movement Box 26 is coupled out. The first set of partially reflective surfaces 17 is oriented such that a portion of the image illumination propagating within the LOE 12 from the incoupling region (coupling prism 15 ) by internal reflection at the main outer surface is deflected towards the second region 18 .

The angular spread of one dimension of the projected image from image projector 14 is represented in FIG. 2A by the illumination cone extending from the POD aperture on the right side of the LOE towards the left side of the LOE. In the non-limiting example shown here, the central optical axis of the POD defines a propagation direction within the LOE aligned with the X-axis, and the angular spread (within the LOE) is approximately ±16°. (It should be noted that the angular FOV becomes larger in air due to the change in refractive index). A first set of partially reflective surfaces 17 is shown in the first region 16 and a second set of partially reflective surfaces 19 is shown in the second region 18 .

Near-eye displays are designed to provide the full field of view of the projected image to the user's eyes, where the user's eyes are located in the area represented by the "Eye Movement Box" (EMB) 26 (i.e., the shape generally represented as a rectangle, with the pupils from which the eye will view at a position within the range of allowed positions specified by the plane of the LOE where the image is projected). In order to reach the eye box, light must be coupled out from the second region 18 towards the EMB 26 through the second set of partially reflective surfaces 19 . To provide a full image field of view, each point in the EMB must receive the entire angular range of the image from the LOE. Tracing the field of view from the EMB may indicate a larger rectangle 28 from which relevant illumination is coupled out from the LOE towards the EMB.

Figure 2A shows the first end of the field of view, which corresponds to the lower left pixel of the projected image. A beam of light coupled into the LOE having a width corresponding to the projector's optical aperture is shown propagating leftward and upward from the POD and being partially reflected from a series of partially reflective surfaces 17 . As shown here, only a subset of the facets generate reflections useful for providing the corresponding pixel in the image viewed by the user, and only a subregion of these facets contribute to the observed image for that pixel. The region of interest is shown with thick black lines, and the rays corresponding to that pixel in the redirected image are shown reflected from facet 17 and then coupled out by facet 19 to the four corners of EMB 26 . Here, and throughout the specification, it will be noted that only the in-plane direction of propagation of the light rays during propagation within the LOE is shown here, but the light rays actually follow zigzag paths of repeated internal reflections from the two major outer surfaces, and a full-dimensional image The field of view is encoded by the oblique angle of the light relative to the main outer surface corresponding to the pixel position in the Y dimension. As an additional example, the deflected and outcoupled rays viewed at the upper left corner of the EMB corresponding to the upper left end of the image are shown with dotted lines.

Figure 2B shows the same configuration as Figure 2A, but here shows the rays reaching the four corners of the EMB corresponding to the lower right pixel of the field of view, where the relevant areas of the relevant partially reflective surface 17 are also shown with bold lines .

Clearly, by additionally tracing the corresponding ray paths for all fields (directions or pixels) of the image reaching all regions of the EMB, it is possible to mark the propagation within the LOE starting from the incoupling region, deflected by one of the first set of partially reflective surfaces and The envelope of all ray paths coupled out by one of the second set of partially reflective surfaces in the direction to the eye box, and this envelope defines the "imaging area" in each facet 17 of the The remainder outside the envelope is the "non-imaging area", where the "imaging area" is needed to deflect the part of the image illumination that contributes to the image reaching the EMB, the "non-imaging area" does not contribute to the desired image. A simplified outline of this envelope corresponding to the "imaging area" of all facets 17 is shown in bold in Figure 2C.

According to a particularly preferred set of implementations of the invention, the facets 17 are realized as "partial facets", so that the partial reflective properties are only present in a sub-region of the cross-sectional area of the region 16, which sub-region includes each facet plane and preferably excludes at least a substantial portion of the "non-imaging area" of some or all of the facets. Such an implementation is schematically shown in Figure 2D. The effective (partially reflective) area of the facets preferably extends slightly beyond the minimum required to fulfill the geometrical requirements of the EMB image projection, to avoid anomalies that might be caused by imperfections at the coating edges, and in some cases the facets can also This is further extended to achieve improved image uniformity due to additional considerations related to integer overlap between facets in deflected image directions. According to some particularly preferred implementations, as shown, the distance of the furthest partially reflective facet encountered along a line from the in-coupling position increases with angle It gradually increases clockwise away from the boundary with the second region 18 .

In the case where the first region 16 is formed from a stack of coated sheets which are then cut at an appropriate angle (eg as described in PCT Patent Publication No. WO2007054928A1 and as known in the art), the partially reflective surface The selective spatial deployment can advantageously be realized to form a stack of plates in which the partially reflective coating is located on a first part of the interface plane between the two plates, while a second part of the interface plane is bonded (typically using index matching adhesive and no coating) to form an optical continuum between the two plates. The selective application of partially reflective coatings is usually achieved by applying a suitable masking layer prior to the coating process and removing the masking layer at the end of the coating process.

According to an alternative production technique, a stack of full-area coated plates can be formed and then cut into the shape required for the volume containing the facets (eg, corresponding to the faceted areas shown in FIG. 2D ). The desired form of the LOE is then accomplished by optically bonding this irregular mass containing partially reflective facets together with a complementary mass of pure index matching glass.

Figure 2E is similar to Figure 2D, but shows an optical system in which the first set of partially reflective surfaces 17 has non-uniform spacing between the planes of the surfaces such that adjacent partially reflective The spacing between the surfaces is smaller than the spacing between adjacent partially reflective surfaces remote from the in-coupling region. This variable spacing is preferred in many cases for enhancing the uniformity of the projected image, as will be explained further below.

The optical axis is not actually parallel to the X axis, but lies in the X-Z plane, where the Z component into the page is chosen such that the entire angular range in the depth dimension of the FOV experiences total internal reflection at the surface of the main substrate. For simplicity of presentation, the graphical representations and descriptions herein will refer only to the in-plane (X-Y) component of the direction of light propagation, referred to herein as the "in-plane component" or "the component parallel to the main outer surface of the LOE" .

It should be noted that the uppermost ray directions in the field of view correspond to the left side of the field of view reaching the observer's eyes, while the lowest ray directions correspond to the right side of the field of view. It should also be noted that some reflections to the left of the field of view are reflected from facets near the right of the LOE in directions that will not reach the EMB, and will thus be lost. Similarly, some rays from the right side of the field of view reflect off the facet near the left side of the LOE and are deflected in directions that will not reach the EMB, and thus will be lost. Certain aspects of the invention take advantage of these observations to reduce the size (and thus volume and weight) of the first LOE (or LOE region).

In particular, FIG. 2F shows shaded areas in FIG. 2E that do not contribute to the image reaching the EMB, and thus can be truncated without interfering with the projection of the image to the user's eyes. It should also be noted that the optical aperture used to inject the image from the image projector is in the lower half of the first region 16 of the LOE 12, since the portion of the image corresponding to the downwardly angled rays shown corresponds to the image field of view The right side of the image field of view need not be reflected from facets that are closer to the left portion of the first region 16 . This allows for a relatively compact implementation of the first region 16 of the LOE 12 . Specifically, the extent of the LOE below the POD optical axis is chosen such that rays from the POD aperture corresponding to the rightmost pixels of the field of view reach facets that deflect the rays towards the entire area of the EMB, but the facets are at such angles that Shortened in areas that can no longer reach the EMB. The reduction in the height of the first region 16 also results in a small reduction in the X dimension because the reduction in the LOE height brings the facets closer to the EMB, and thus reduces the required X dimension to cover the desired angular range of the FOV. Here and elsewhere in this document, it will be noted that the terms "cut out" and "truncated" are used to refer to a reduced geometry or size of the final product relative to a theoretical starting point for an implementation such as FIG. 2A as a point of reference. The term does not carry any implementation of physically cutting away material or any other specific production technique. It is not necessarily contemplated that the LOE will be truncated precisely along the boundaries of the indicated regions, but rather that these regions provide design flexibility, allowing for any external Contour to complete the LOE.

It should be noted that the use of partial facets as described above with reference to FIGS. The second LOE region does not need to traverse so many additional facets before. Further advantages are shown here with reference to FIGS. 3A and 3B .

In particular, Figure 3A shows the region of the facet labeled 17' outside the envelope of the facet region required to deliver the projected image to the EMB. (This facet is usually one of many, but is shown here alone for easier explanation of its significance.) Figure 3A shows downwardly pointing image rays originating at the image projector A ray path that passes directly through a partially reflective surface. This ray travels (propagating by total internal reflection) into a second region 18 where it is incident on one of the second set of partially reflective surfaces 19 and is partially reflected as shown, generating upward Undesirable “ghost” reflections propagating back into the first region 16 . The angle of the light rays is such that the light rays may be reflected from the continuation of the facet 17' in a direction towards the EMB 24, in which case the light rays may form visible ghost images which interfere with viewing the image.

Figure 3B shows in contrast what happens to the same ghosted raypath where the facets are only deployed in a reduced area at or near the area needed to form the output image. In this case, light rays reflected from the surface 19 and directed back to the first region 16 will not encounter any partially reflecting surface as they travel through the first region of the LOE. Thus, the light continues to travel until reaching the outer edge of the LOE where it is preferably absorbed or diffused by suitably placed non-reflective surfaces.

In the example of FIGS. 2A-2F , the size of the first LOE region 16 above the optical axis of the POD 14 cannot be significantly reduced because the leftmost region of the FOV must be reflected from the facet at the leftmost end of the LOE. 4A-5B illustrate an alternative approach according to an additional feature of some particularly preferred implementations of the invention, which allows for a further reduction in the size of the first LOE region 16 .

Specifically, in the device of FIG. 4A , the POD and/or incoupling prisms are rotated such that the central optical axis of image projection is angled downward across the first LOE region 16, where the angle is most preferably selected so as to be approximately parallel to The X axis projects the leftmost end of the FOV. In this case, the incoupling of the POD is preferably at or near the upper end of the first LOE region 16 (typically in the upper third). The required size of the LOD below the POD aperture is dictated by geometrical considerations similar to those described with reference to FIGS. The corresponding area of FOV is transmitted to the whole EMB. In this case, the rightmost ray descends at a steeper angle, and the facet angle is adjusted accordingly, but the overall Y dimension of the first LOE is still further reduced.

In some cases, and particularly emphasized by the steeper angles shown on the right side of the field of view in Figure 4A, the geometrical requirements to "fill" the EMB require a significantly different small plane spacing. Thus, in the example shown in Figure 4A, for the incoupling optical aperture widths as shown, one side of the pixel beam reflected from one facet coincides with the other side of the beam reflected from the adjacent facet. Effectively filling left field. However, on the right side of the field, the uniform facet spacing as shown will result in a "black line" (shown here as a thick black line) within which there is no image illumination. If the facet spacing decreases uniformly, this will lead to the inverse problem of bright fringes near the left side of the field. To address this problem, variable facet spacing is preferred, as shown in Figure 4B with a partial collection of facets with corresponding geometric configurations, showing how to properly tune the facet spacing to provide a " Filled" EMB's image illuminated. The facet spacing preferably varies gradually (but not necessarily continuously or linearly) across the LOE region 16 .

As described above with respect to FIGS. 2A-2E , the regions of each facet needed to provide partial reflection to fill the EMB image for each field (pixel) of the image can be identified, such as for the two end fields in FIG. 4C Show. Here too, by defining an "envelope" of all regions including all facets required to provide an output image at the eye box 26, it is also possible in a manner completely similar in structure and function to that described above with reference to Figures 2D and 2E. A first region 16 of the LOE 12 is implemented having selectively deployed partially reflective surfaces whose extents vary across the first region. A corresponding implementation of the overall optical system for this case is shown in FIG. 5A . Figure 5B shows various additional areas of the first and second LOEs that do not contribute to image projection and can be further cut out as shown, depending on the needs of each particular application.

Therefore, by deploying the image projector 14 and tilting the in-plane component of the optical axis of the propagating image relative to the X-axis towards the boundary of the second region 18, and most preferably ensuring that the in-plane component of one end of the field of view of the propagating image is substantially Parallel to the X axis, further compactness can be achieved compared to the overall configuration of FIGS. 2A to 2F . In all other respects, the structure, function and range of options for implementing the apparatus of Figures 4A-5B are as described above with reference to Figures 2A-3B.

In addition to the tilting of the optical axis direction of the image projector described in FIGS. 4A-5B , many other angular parameters can be used to achieve various adjustments to the characteristics of the optical system. Various examples thereof will now be shown with reference to FIGS. 6A to 6D and 7 .

Referring first to FIGS. 6A and 6B , these illustrate the geometry of potential adjustments to eye box position across the width dimension of the second region of the LOE 12 . In Fig. 6A, a device corresponding to Figs. 2A to 2F is shown, wherein the ray paths correspond to the central ray of the image viewed from the center of the eye box. This results in a central localization of the EMB.

Figure 6B shows the effect of implementing the second region 18 of the LOE 12 in which the facets 19 are angularly offset with respect to the X-axis. In this case, the rays forming the center of field at the center of the eye box are displaced, resulting in a horizontally shifted eye box, which is useful where an asymmetric deployment of the EMB relative to the LOE is required. In this context, the "direction of extension" of a facet is considered to be the intersection of the facet with a plane parallel to the main outer surface of the LOE. The equivalent definition is the line of intersection between the plane containing the partially reflective surface and the main exterior surface. This line is referred to herein as the direction of extension of the facet parallel to the main outer surface, or the "in-plane" direction of extension. In this context, the degree of "angular offset" relative to the X-axis depends on the degree of horizontal offset required, but for some preferred cases, the offset can be in the range of 5 degrees to 25 degrees, but more Small and larger angular offsets are possible.

Turning to FIGS. 6C and 6D , another form of adjustment is shown that allows corrections for "face curvature" and/or angle of convergence, as shown in FIG. 7 . Specifically, FIG. 7 schematically shows a top view of a near-eye display in which the LOEs are deployed obliquely relative to each other, allowing the LOEs to be mounted in a "wrap-around" frame shaped to follow ( To some extent) the side-to-side curvature of the face. To achieve stereopsis in such a configuration, it is necessary to correct for the curvature of the face so that the image is rendered centrally along parallel lines in space (dot-dash lines in Figure 7), which are horizontally offset from the vertical of the LOE . Additionally or alternatively, in various applications, particularly but not exclusively for indoor use, it is desirable to provide a convergence angle between two displays such that objects viewed binocularly through the displays appear to be located in a user's desired direction. This correction also requires a deflection from the normal to the LOE plane with a component in the horizontal (X-axis) direction.

To achieve this correction, the image projector 14 and the first set of partially reflective surfaces 17 are oriented such that the propagated image coupled into the LOE from the image projector 14 is deflected by the facet 17 to generate light at an angle relative to the Y-axis A deflected propagation image of the in-plane component propagation of the axis. After outcoupling by the facet 19, the result of this offset is that the optical axis of the outcoupled image is deflected in a horizontal plane, i.e. inclined with respect to the normal of the main outer surface, with a facet along the second set of partially reflective surfaces A non-zero tilt component in the direction of the inner extension, as shown in Figure 6D.

Although these adjustments have been presented as independent adjustments, it should be noted that various parameters such as projector optical axis tilt, first LOE region facet angle, and second LOE region facet angle are interrelated, and one of these parameters Changes in ϕ will typically require corresponding adjustments of other parameters to ensure transmission across the field of view, and these adjustments can cause the injected image to rotate about its central axis, which can be directly corrected by rotation of the projector and/or coupling device, as shown in Figure 6D shown schematically in .

As mentioned above in the context of Figure 1B, all of the above principles can also be applied to the "sideways" configuration, where the image is injected from a POD located laterally outside the viewing zone and is captured by a first set of small The plane is extended vertically and then horizontally by a second set of facets for coupling into the user's eyes. It should be understood that all of the above configurations and variations also apply to side injection configurations.

Throughout the above description, reference has been made to the X-axis and Y-axis as shown, wherein the X-axis is horizontal or vertical and corresponds to the first dimension of optical aperture expansion, and the Y-axis is the second dimension of expansion. corresponding to the other axis. In this context, X and Y may be defined relative to the orientation of the device when the device is mounted on the user's head in an orientation typically defined by a support device (eg, the eyeglass frames of FIGS. 1A and 1B described above). Other terms generally consistent with the definition of the X-axis include: (a) at least one straight line bounding the eye box, which may be used to define a direction parallel to the X-axis; (b) the edges of the rectangular projected image generally parallel to the The X-axis and the Y-axis; and (c) the boundary between the first region 16 and the second region 18 extends generally parallel to the X-axis.

The present invention also includes the following technical solutions:

1. An optical system for directing image illumination injected at an in-coupling region to an eye box for viewing by a user's eye, said optical system comprising a light-guiding optical element (LOE) formed of a transparent material, said LOEs include:

(a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation;

(b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to said first orientation;

(c) a set of mutually parallel major exterior surfaces extending across said first region and said second region such that said first set of partially reflective surfaces and said second set of partially reflective surfaces are both between said major exterior surfaces,

wherein the second set of partially reflective surfaces is at an oblique angle to the major outer surface such that internal reflections at the major outer surface propagate within the LOE from the first region to the second region A portion of image illumination is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that internal reflection from the in-coupling region through the main outer surface is at a portion of the image illumination propagating within the LOE is deflected towards the second region,

wherein each of said partially reflective surfaces of said first set of partially reflective surfaces comprises a partially reflective coating at an interface plane between two plates forming part of said LOE, and wherein said partially reflective A coating is on a first portion of the interface plane and at least one of the partially reflective surfaces has a second portion of the interface plane bonded to form an optical continuum between the two plates.

2. The optical system of clause 1, wherein propagating within the LOE from the in-coupling region, is deflected by one of the first set of partially reflective surfaces and is transmitted by the second set of partially reflective surfaces The envelope of the path of light rays outcoupled by one of the partially reflective surfaces in a direction to the eye box defines an imaging area of the one of the partially reflective surfaces of the first set of partially reflective surfaces, and wherein, A region of the one of the first set of partially reflective surfaces outside the envelope defines a non-imaging region of the one of the first set of partially reflective surfaces, wherein Most of the non-imaging areas are combined to form an optical continuum between the two plates.

3. The optical system of clause 1, wherein the first set of partially reflective surfaces has a non-uniform spacing such that the spacing between adjacent partially reflective surfaces near the incoupling region is smaller than that farther from the incoupling region. The spacing between adjacent partially reflective surfaces of a region.

4. The optical system according to claim 1, wherein the optical system further comprises an image projector for projecting a collimated image having an angular field of view around an optical axis, the image projector optical coupled to the LOE to introduce the collimated image into the LOE at the in-coupling region as a propagated image propagated within the LOE by internal reflection at the major exterior surface, the propagated An image is partially reflected by the first set of partially reflective surfaces to generate a deflected propagating image propagating within the LOE by internal reflection at the major exterior surface, the deflected propagating image being propagated by the second set of a partially reflective surface is partially reflective to generate an out-of-coupling image directed outwardly from one of the main exterior surfaces to the eye box, the optical axis of the out-coupling image being inclined relative to a normal to the main exterior surface , having a non-zero tilt component along the direction of in-plane extension of the second set of partially reflective surfaces.

5. The optical system of aspect 1 configured to project an image to the eye box with a main axis comprising an X axis corresponding to a first horizontal or vertical axis of the projected image, and to the The other axis of the projected image corresponds to the Y axis, and wherein the second set of partially reflective surfaces has an extension direction parallel to the main outer surface, the extension direction having an angular offset relative to the X axis.

6. The optical system of aspect 1 configured to project an image to the eye box with a main axis comprising an X axis corresponding to a first horizontal or vertical axis of the projected image, and a first axis corresponding to the projected image. The Y-axis corresponding to the other axis of the projected image, the optical system also includes an image projector for projecting a collimated image with an angular field of view around the optical axis, the image projector optically coupled to the LOE to introduce the collimated image into the LOE at the in-coupling region as a propagating image propagating within the LOE by internal reflection at the major exterior surface, the propagating image The in-plane component of the optical axis is inclined relative to the X-axis towards the boundary of the second region.

7. The optical system of clause 6, wherein an in-plane component of one end of the field of view of the propagating image is substantially parallel to the X-axis.

8. The optical system of aspect 1 configured to project an image to the eye box with a primary axis, wherein the primary axis includes an X-axis corresponding to a first horizontal or vertical axis of the projected image, and Y-axis corresponding to the other axis of the projected image, the optical system further includes an image projector for projecting a collimated image having an angular field of view around the optical axis, the image projector optically coupled to the LOE to introduce the collimated image into the LOE at the incoupling region as a propagated image propagating within the LOE by internal reflection at the major exterior surface, the The propagated image is partially reflected by the first set of partially reflective surfaces to generate a deflected propagated image propagated within the LOE by internal reflection at the major exterior surface, the light of the deflected propagated image The in-plane component of the axis is tilted with respect to the Y-axis.

9. An optical system for projecting an image injected at an in-coupling region for viewing by a user's eye at an eye box, the image being viewed with a main axis comprising a horizontal or vertical axis to the projected image an X-axis corresponding to the straight axis, and a Y-axis corresponding to an axis perpendicular to the X-axis of the projected image, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOE comprising:

(a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation;

(b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to said first orientation;

(c) a set of mutually parallel major exterior surfaces extending across said first region and said second region such that said first set of partially reflective surfaces and said second set of partially reflective surfaces are both between said major exterior surfaces,

wherein the second set of partially reflective surfaces is at an oblique angle to the major outer surface such that internal reflections at the major outer surface propagate within the LOE from the first region to the second region A portion of image illumination is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that internal reflection from the in-coupling region through the main outer surface is at a portion of the image illumination propagating within the LOE is deflected towards the second region,

And wherein said second set of partially reflective surfaces has a direction of extension parallel to said major outer surface, said direction of extension having an angular offset relative to the X-axis.

10. An optical system for projecting an image injected at an in-coupling region for viewing by a user's eye at an eye box, said image being viewed with a main axis comprising a horizontal or vertical axis to the projected image An X-axis corresponding to the straight axis, and a Y-axis corresponding to an axis perpendicular to the X-axis of the projected image, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOE comprising:

(a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation;

(b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to said first orientation;

(c) a set of mutually parallel major exterior surfaces extending across said first region and said second region such that said first set of partially reflective surfaces and said second set of partially reflective surfaces are both between said major exterior surfaces,

wherein the second set of partially reflective surfaces is at an oblique angle to the major outer surface such that internal reflections at the major outer surface propagate within the LOE from the first region to the second region A portion of image illumination is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that internal reflection from the in-coupling region through the main outer surface is at a portion of the image illumination propagating within the LOE is deflected towards the second region,

The optical system also includes an image projector for projecting a collimated image having an angular field of view about an optical axis, the image projector optically coupled to the LOE for The collimated image is introduced into the LOE at the region as a propagated image propagating within the LOE by internal reflection at the major exterior surface, the in-plane component of the optical axis of the propagated image relative to the The X-axis is inclined toward the boundary of the second region.

11. The optical system of clause 10, wherein an in-plane component of one end of the field of view of the propagating image is substantially parallel to the X-axis.

12. An optical system for projecting an image injected at an in-coupling region for viewing by a user's eye at an eye box, said image being viewed with a main axis comprising a horizontal or vertical axis to the projected image an X-axis corresponding to the straight axis, and a Y-axis corresponding to an axis perpendicular to the X-axis of the projected image, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOE comprising:

(a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation;

(b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to said first orientation;

(c) a set of mutually parallel major exterior surfaces extending across said first region and said second region such that said first set of partially reflective surfaces and said second set of partially reflective surfaces are both between said major exterior surfaces,

wherein the second set of partially reflective surfaces is at an oblique angle to the major outer surface such that internal reflections at the major outer surface propagate within the LOE from the first region to the second region A portion of image illumination is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that internal reflection from the in-coupling region through the main outer surface is at a portion of the image illumination propagating within the LOE is deflected towards the second region,

The optical system also includes an image projector for projecting a collimated image having an angular field of view about an optical axis, the image projector optically coupled to the LOE for introducing the collimated image into the LOE at the region as a propagated image propagated within the LOE by internal reflection at the major exterior surface, the propagated image being partially reflected by the first set of partially reflective surfaces , to generate a deflected propagating image propagated within the LOE by internal reflection at the major exterior surface, the in-plane component of the optical axis of the deflected propagating image being inclined with respect to the Y-axis.

13. The optical system according to any one of clauses 5 to 12, wherein the eye box is bounded by at least one straight line parallel to the X-axis.

14. The optical system of any one of clauses 5 to 12, wherein the projected image is a rectangular image with edges parallel to the X-axis and the Y-axis.

15. The optical system of any one of clauses 5 to 12, further comprising support means configured to support the LOE relative to the user's head, wherein the major outer surface One faces the user's eye and is oriented such that the X-axis is oriented horizontally relative to the user's eye.

16. The optical system of any one of clauses 5 to 12, wherein the first region and the second region are separated by a boundary extending parallel to the X-axis.

17. An optical system for directing image illumination injected at an in-coupling region to an eye box for viewing by a user's eye, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOEs include:

(a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation;

(b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to said first orientation;

(c) a set of mutually parallel major exterior surfaces extending across said first region and said second region such that said first set of partially reflective surfaces and said second set of partially reflective surfaces are both between said major exterior surfaces,

wherein the second set of partially reflective surfaces is at an oblique angle to the major outer surface such that internal reflections at the major outer surface propagate within the LOE from the first region to the second region A portion of image illumination is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that internal reflection from the in-coupling region through the main outer surface is at a portion of the image illumination propagating within the LOE is deflected towards the second region,

And wherein the first set of partially reflective surfaces has a non-uniform spacing such that the spacing between adjacent partially reflective surfaces close to the in-coupling region is smaller than the spacing between adjacent partially reflective surfaces away from the in-coupling region interval.

18. An optical system for directing image illumination injected at an in-coupling region to an eye box for viewing by a user's eye, the optical system comprising a light-guiding optical element (LOE) formed of a transparent material, the LOEs include:

(a) a first region comprising a first set of planar mutually parallel partially reflective surfaces having a first orientation;

(b) a second region comprising a second set of planar mutually parallel partially reflective surfaces having a second orientation non-parallel to said first orientation;

(c) a set of mutually parallel major exterior surfaces extending across said first region and said second region such that said first set of partially reflective surfaces and said second set of partially reflective surfaces are both between said major exterior surfaces,

wherein the second set of partially reflective surfaces is at an oblique angle to the major outer surface such that internal reflections at the major outer surface propagate within the LOE from the first region to the second region A portion of image illumination is coupled out from the LOE towards the eye box, and wherein the first set of partially reflective surfaces is oriented such that internal reflection from the in-coupling region through the main outer surface is at a portion of the image illumination propagating within the LOE is deflected towards the second region,

The optical system also includes an image projector for projecting a collimated image having an angular field of view about an optical axis, the image projector optically coupled to the LOE for introducing the collimated image into the LOE at the region as a propagated image propagated within the LOE by internal reflection at the major exterior surface, the propagated image being partially reflected by the first set of partially reflective surfaces , to generate a deflected propagating image propagating within the LOE by internal reflection at the primary exterior surface, the deflected propagating image being partially reflected by the second set of partially reflective surfaces to generate one of the outer surfaces points outwardly towards the out-coupling image of the eye box, the optical axis of the out-coupling image is inclined relative to the normal of the main outer surface, with a face along the second set of partially reflective surfaces Non-zero slope component of the direction of inward extension.

It should be understood that the above description is intended as an example only, and that many other embodiments are possible within the scope of the invention as defined in the appended claims.

Claims (8)

1. A head-mounted display for displaying images to the eyes of a user, the head-mounted display comprising: (a) a light guiding structure formed of a transparent material having a set of mutually parallel major surfaces for supporting the propagation of light within said light guiding structure by internal reflection at said major surfaces; (b) support means for supporting the light guide structure on the head of the user, wherein one of the major surfaces is in facing relation to the user's eyes, and the light guide the horizontal axis of the structure is parallel to the line between the user's pupils; and (c) an image projector optically coupled to said light guide structure to introduce light corresponding to a collimated image to propagate within said light guide structure in a first direction by internal reflection at said major surface, Wherein the light guide structure includes a first set of partially reflective inner surfaces and a second set of partially reflective inner surfaces, the first set of partially reflective inner surfaces being arranged to progressively deflect light propagating in the first direction to pass through the internal reflection at the major surface propagates in a second direction within the light guiding structure, and the second set of partially reflective inner surfaces is arranged to progressively deflect light propagating in the second direction away from the light guiding structure coupled out toward the user's eyes, And wherein a substantial portion of both the first set of partially reflective inner surfaces and the second set of partially reflective inner surfaces are located within a viewing area of the light guide structure through which the user's eyes can view distant scene. 2. An optical system for directing light corresponding to a collimated image projected by a projector to be visible to the eyes of a user, the optical system comprising: (a) a first light guide portion having parallel, planar front and rear major exterior surfaces that support passage of light between the front and rear major exterior surfaces Propagation of internal reflection at the rear major outer surface within said first light guide portion, said first light guide portion being surrounded by a set of edges including a flat lower edge, said first light guide portion comprising a set of mutually parallel planar interior partially reflective surfaces oriented such that light propagating within said first light guide portion by internal reflection with an in-plane component along a first direction is received by said partially reflective surface is progressively deflected to propagate within said first lightguide portion by internal reflection with an in-plane component along a second direction, said second direction being non-parallel to said first direction; (b) a second lightguide portion optically joined to said first lightguide portion at said flat lower edge to form a continuation of said first lightguide portion, said second lightguide portion having parallel, flat The front and rear major outer surfaces of the second light guide portion are a continuation of the front and rear major outer surfaces of the first light guide portion , the second light guide portion has a set of mutually parallel, planar inner partially reflective outcoupling surfaces inclined obliquely relative to the front and rear major outer surfaces, wherein the second light guide A portion has a width in a direction parallel to the flat lower edge, the width of the second light guide portion gradually decreases with increasing distance from the flat lower edge. 3. A head-mounted display for displaying images to the eyes of a user, the head-mounted display comprising: (a) a light guiding structure formed of a transparent material having a set of mutually parallel major surfaces for supporting the propagation of light within said light guiding structure by internal reflection at said major surfaces; (b) support means for supporting the light guide structure on the head of the user, wherein one of the major surfaces is in facing relation to the user's eyes, and the light guide the horizontal axis of the structure is parallel to the line between the user's pupils; and (c) an image projector optically coupled to said light guide structure to introduce light corresponding to a collimated image to propagate within said light guide structure in a first direction by internal reflection at said major surface, Wherein the light guide structure includes a first set of partially reflective inner surfaces and a second set of partially reflective inner surfaces, the first set of partially reflective inner surfaces being arranged to progressively deflect light propagating in the first direction to pass through the internal reflection at the major surface propagates in a second direction within the light guiding structure, and the second set of partially reflective inner surfaces is arranged to progressively deflect light propagating in the second direction away from the light guiding structure coupled out toward the user's eyes, And wherein each of said second set of partially reflective inner surfaces has a direction of elongation corresponding to a line of intersection between said partially reflective inner surface and a plane parallel to said major surface, said direction of elongation inclined to the horizontal axis of the light guiding structure. 4. The head-mounted display of claim 3, wherein the first set of partially reflective inner surfaces is angled such that the second direction is substantially perpendicular to the second set of partially reflective inner surfaces. direction of elongation. 5. A display for displaying images to the eyes of a user, the display comprising: (a) a lightguide structure formed of a transparent material, the lightguide structure having a pair of mutually parallel major surfaces defining a plate-like lightguide that supports light passing through the major surfaces Propagation of internal reflection at the light guide structure; and (b) an image projector optically coupled to said light guide structure to introduce light corresponding to a collimated image to propagate within said light guide structure in a first direction by internal reflection at said major surface, Wherein the light guide structure includes a first set of partially reflective inner surfaces and a second set of partially reflective inner surfaces, the first set of partially reflective inner surfaces being arranged to progressively deflect light propagating in the first direction to pass through the internal reflection at the major surface propagates in a second direction within the light guiding structure, and the second set of partially reflective inner surfaces is arranged to progressively deflect light propagating in the second direction away from the light guiding structure coupled out toward the user's eyes, And wherein said image projector projects a rectangular collimated image having an angular spread of a ray direction around a first axis corresponding to a width of said collimated image and a The height corresponds to the angular spread of the ray direction along the second axis, and wherein the collimated image appears on the The light guide structure propagates along the first direction. 6. The display of claim 5, wherein the image projector and the first and second sets of partially reflective inner surfaces are oriented such that light outcoupled by the eye is inclined at an offset angle with respect to the normal to said major surface, with a non-zero oblique component along an in-plane extension of said second set of partially reflective inner surfaces, said elongation corresponding to An intersection line between the partially reflective inner surface and a plane parallel to the major surface. 7. The display of claim 6, further comprising support means for supporting the light guide structure on the user's head, wherein one of the major surfaces is aligned with the The user's eyes are in facing relationship, and wherein the offset angle corrects a facial curvature angle of the light guide structure relative to the user's eyes. 8. The display of claim 6, further comprising support means for supporting the light guide structure on the user's head, wherein one of the major surfaces is aligned with the The user's eyes are in facing relationship, and wherein the offset angle provides a convergence angle for images viewed by the user's eyes.

Images